Pros: Higher than original capacity replacement internal batteries add no bulk to iPods, but enhance their power at reasonable prices. Two-year warranty gives assurance of longer-term iPod performance than other options, the single biggest factor in our ratings of these products. Self-installation and pro installation options available.

Cons: Somewhat higher priced than top self-installation competitor. Installation may challenge or deter some users; 3G installation is more challenging and likely to damage plastic around the Dock Connector. Early run of 1G/2G batteries had serious issue, remedied in current shipping units.

Most of the batteries sold for the iPod are external - that is, they strap on to an iPod’s back and add additional power to its internal battery. But if the internal battery alone isn’t keeping up with its old performance levels, or fails outside of its warranty period, there are ways to replace it. FastMac’s TruePower batteries ($29.95-$39.95) are one of two options we’ve reviewed, and several that we’ve tested.

As each TruePower kit comes with one battery, two blue plastic iPod-opening tools, and an installation instruction card, you can either self-install TruePower in your iPod, or pay FastMac a fee ($39.95) to do it for you. While the installation process isn’t difficult - we documented the challenges in our review of Other World Computing’s competing NuPower batteries (iLounge rating: A/A-) - people without nimble fingers should have the work done for them by tech-inclined friends, and all 3G users should be careful to avoid damage to the plastic around the bottom Dock Connector port. Our advice is to move slowly, wear a pair of gloves, and start by depressing the unit’s rear Apple logo before inserting the blue prying tools - it makes the process a lot easier.

Why prefer one battery to the other? FastMac claims that TruePower batteries will last longer than their competitors - for two years of regular use - a claim which is hard to verify without testing each battery for that length of time, or connecting an iPod to a battery and repeatedly charging and discharging hundreds of times. And to be fair, you’d have to run the same tests on each of its competitors to see how they do by comparison. As such, we didn’t feel comfortable offering confirmation of this claim, and went to FastMac with the following question: what happens if a consumer has problems during the two years?

“Simple,” FastMac’s representative told us. “If you don’t get 70% of the original charge, you are eligible for a replacement.” To that end, if you have a problem within the two-year warranty period, the company will test your battery to see if it has less than 70% of its original chemical capacity, and inspect it to be sure that you haven’t abused or damaged it. Then you’ll get a replacement. As anyone who has dealt with Apple’s original iPod batteries knows, this is a better deal than Apple’s current $66 replacement plan by a wide margin.

That’s good news, as is the fact that two of the currently shipping batteries we tested performed well, but not always up to the company’s peak numbers. Our testing procedure is always the same: iPod on medium volume, no equalizers, earbuds attached, with randomized playback through a huge library of different songs. Under these conditions, the third-generation TruePower routinely ran for over 9 hours per charge, once going for 9 hours and 17 minutes, once for 9 hours and 50 minutes, and once for a full 10 hours, the peak of FastMac’s claims. This isn’t a huge jump over the 3G iPod’s initial typical run time, but it’s superior, especially if sustained over the battery’s life. By comparison, the 1G/2G TruePower ran once for 16 hours in 3 minutes, once 16 hours and 15 minutes, and once for 17 hours and 18 minutes.

These numbers are comparable to Newer Technology’s numbers, but short of FastMac’s claimed “up to 22 hours” by a bit. For reference, we had the same “lower than peak” experience when testing the NuPower batteries, but felt then (as now) that the performance was so substantially better than Apple’s batteries that the difference didn’t matter - too much. Based on our experiences, we plan to be more critical of overaggressive marketing when we review the performance claims of 4G and other iPod internal replacement batteries in the future.

We had only one bad experience with a TruePower battery, which we feel obliged to report just in case anyone else experiences the same thing. While our 3G battery worked without problems, our original 1G/2G battery was manufactured too large, and when installed according to directions was actually causing our test iPod’s hard drive and controls to have very serious problems - the mark of our F rating. However, FastMac has remedied the problem in units that have been shipping for the past month, and provided us a unit that we’ve been testing without any similar issues. As such, we are rating the currently shipping product, not its predecessor. We reserve the right to revisit this issue and our rating if we hear that readers are having problems of any sort with their batteries.

So what’s a fair way to rate these batteries by comparison with the NuPower options, which perform about the same right now, and sell for less (now $29.99 versus $39.95 for the 1G/2G batteries, $29.95 versus $25.99 for the 3G batteries), but only have a one-year warranty? We consider the options roughly equivalent. Both companies make products that will provide older iPod owners with superior alternatives to Apple’s internal batteries, at a lower - self-installed - price. If you want to pay less, go with NuPower. If you don’t mind paying a little bit more and want the two-year warranty, go with TruePower. It’s hard to lose with either option.

Editors' Note: iLounge only reviews products in "final" form, but many companies now change their offerings - sometimes several times - after our reviews have been published.
This iLounge article provides more information on this practice, known as revving.